Degenerative disorders of the intervertebral discs (IVDs) are generally characterized by enhanced matrix degradation, angiogenesis, innervation, and increased expression of catabolic cytokines. In this study, we investigated the effects of inflammatory cytokines, IL‐1β, and TNF‐α, on the expression of an angiogenic factor, vascular endothelial growth factor (VEGF), and neurotrophic factors, nerve growth factor (NGF) and brain‐derived neurotrophic factor (BDNF), in human IVD degeneration. IL‐1β and TNF‐α stimulated the gene expression of VEGF, NGF, and BDNF in nucleus pulposus (NP) cells isolated from patient tissues. Immunohistochemical results demonstrated a positive correlation between IL‐1β and VEGF/NGF/BDNF expression in human IVD tissues. RNA expression analysis of patient tissues also identified positive correlations between VEGF and platelet endothelial cell adhesion molecule‐1 (PECAM‐1) and between NGF/BDNF and protein gene product 9.5 (PGP9.5). Our findings suggest that IL‐1β is generated during IVD degeneration, which stimulates the expression of VEGF, NGF, and BDNF, resulting in angiogenesis and innervation. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:265–269, 2011

The intervertebral disc (IVD) is a complex joint structure comprising three primary components—namely, nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous endplate (CEP). The IVD retrieves oxygen from the surrounding vertebral body through CEP by diffusion and likely generates ATP via anaerobic glycolysis. IVD degeneration is characterized by a cascade of cellular, compositional, structural changes. With advanced age, pronounced changes occur in the composition of the disc extracellular matrix (ECM). NP and AF cells in the IVD possess poor regenerative capacity compared with that of other tissues. Hypoxia-inducible factor (HIF) is a master transcription factor that initiates a coordinated cellular cascade in response to a low oxygen tension environment, including the regulation of numerous enzymes in response to hypoxia. HIF-1α is essential for NP development and homeostasis and is involved in various processes of IVD degeneration process, promotes ECM in NP, maintains the metabolic activities of NP, and regulates dystrophic mineralization of NP, as well as angiogenesis, autophagy, and apoptosis during IVD degeneration. HIF-1α may, therefore, represent a diagnostic tool for early IVD degeneration and a therapeutic target for inhibiting IVD degeneration

Intervertebral discs (IVDs) have poor nutrient diffusion, because the nucleus pulposus (NP) lacks direct vascular supply and likely generates adenosine triphosphate by anaerobic glycolysis. Regulation of glycolysis is mediated by hypoxia-inducible factor-1α (HIF-1α), a transcription factor that responds to local oxygen tension. Constitutively active HIF-1α (CA HIF-1α) was created by point mutation and determined the protective role of HIF-1α in IVD degeneration. Under fluoroscopy, rat caudal IVD segments were stabbed by a needle puncture, and pcDNA3- HIF-1α wild-type (WT) or pcDNA3-CA HIF-1α was transfected into NP cell lines. The constitutive activity of CA HIF-1α was analyzed using a luciferase assay after cell lysis. Next, IVD tissue samples were retrieved from five patients with degenerative lumbar spinal stenosis at the time of surgery, and NP cells were cultured. NP cells were transfected with CA HIF-1α, and relevant gene expression was measured. HIF-1α protein levels in the nucleus were significantly higher, and transcriptional activity was 10.3-fold higher in NP cells with CA HIF-1α than in those with HIF-1α WT. Gene transfer of CA HIF-1α into NP cells enhanced the expression of Glut-1, Glut-3, aggrecan, type II collagen, and Sox9. Moreover, CA HIF-1α reduced the apoptosis of NP cells induced by the Fas ligand. The HIF-1α and collagen 2 expression levels were notably increased in the NP cells of the CA HIF-1α transfected segments in histology and immunohistochemistry study. Collectively, these results suggest that activation of HIF-1α signaling pathway may play a protective role against IVD degeneration and could be used as a future therapeutic agent.

Background: While most studies of Duchenne muscular dystrophy scoliosis focus on technical and radiographic indices, functional status is a more important factor to consider in the management of Duchenne muscular dystrophy. The objectives of the current study were to compare the pulmonary function, radiographic outcome, and functional recovery, with use of validated questionnaires, in surgically and nonsurgically treated patients with Duchenne muscular dystrophy who have scoliosis. Methods: Sixty-six patients (forty treated surgically and twenty-six treated nonsurgically) with a minimum follow-up of two years were included in this study. Forced vital capacity, radiographic parameters (the Cobb angle, lordosis, and pelvic obliquity), and functional status, according to the modified Rancho scale and manual muscle test, were measured preoperatively and at the time of the final follow-up. The Muscular Dystrophy Spine Questionnaire (MDSQ) was completed at the final follow-up evaluation. Results: Pulmonary function, functional scores (manual muscle test and modified Rancho scale), and radiographic measurements, except for lordosis, were similar for both groups at the time of the initial consultation (p > 0.05). At the time of the final follow-up, all radiographic parameters were significantly improved in the surgical group compared with the nonsurgical group. The mean score (and standard deviation) on the manual muscle test was not significantly different between the surgical and nonsurgical groups (23.2 ± 8.3 versus 22.8 ± 6.3; p = 0.828). The mean score on the modified Rancho scale also showed similar results in the groups (3.9 ± 0.3 and 4.04 ± 0.3, respectively; p = 0.088). The surgical group had higher mean MDSQ scores than the nonsurgical group (35.1 ± 14.7 and 26.9 ± 9.9, respectively; p = 0.008). Both groups showed a decrease in forced vital capacity at the time of the final follow-up, but the deterioration of forced vital capacity was significantly slower (p = 0.035) in the surgical group (268 ± 361 mL) than in the nonsurgical group (536 ± 323 mL). Conclusions: Surgery in patients who had Duchenne muscular dystrophy with scoliosis improved function and decreased the rate of deterioration of forced vital capacity compared with patients treated conservatively. However, the muscle power and forced vital capacity decreased in both groups. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Tauroursodeoxycholic acid (TUDCA) is a US FDA-approved hydrophilic bile acid for the treatment of chronic cholestatic liver disease. In the present study, we investigate the effects of TUDCA on the proliferation and differentiation of osteoblasts and its therapeutic effect on a mice model of osteoporosis. Following treatment with different concentrations of TUDCA, cell viability, differentiation, and mineralization were measured. Three-month-old female C57BL/6 mice were randomly divided into three groups (n = 8 mice per group): (i) normal mice as the control group, (ii) ovariectomy (OVX) group (receiving phosphate-buffered saline (PBS) treatment every other day for 4 weeks), and (iii) OVX group with TUDCA (receiving TUDCA treatment every other day for 4 weeks starting 6 weeks after OVX). At 11 weeks post-surgery, serum levels of procollagen type I N-terminal propeptides (PINP) and type I collagen crosslinked C-telopeptides (CTX) were measured, and all mice were sacrificed to examine the distal femur by micro-computed tomography (CT) scans and histology. TUDCA (100 nM, 1 µM) significantly increased the proliferation and viability of osteoblasts and osteoblast differentiation and mineralization when used in vitro. Furthermore, TUDCA neutralized the detrimental effects of methylprednisolone (methylprednisolone-induced osteoblast apoptosis). In the TUDCA treatment group the PINP level was higher and the CTX level was lower, but these levels were not significantly different compared to the PBS treatment group. Micro-CT and histology showed that the TUDCA treatment group preserved more trabecular structures in the distal femur compared to the PBS treatment group. In addition, the TUDCA treatment group increased the percentage bone volume with respect to the total bone volume, bone mineral density, and mice distal femur trabeculae compared with the PBS treatment group. Taken together, our findings suggest that TUDCA may provide a favorable effect on bones and could be used for the prevention and treatment of osteoporosis.

Shin DE, et al. Asian Spine J. 2010 Dec;4(2):123-127. http://dx.doi.org/10.4184/asj.2010.4.2.123